Optical transmission apparatus and transmission method therefor

Patent metadata

Field	Value
Publication number	US-2016274306-A1
Application number	US-201615066850-A
Country	US
Kind code	A1
Filing date	Mar 10, 2016
Priority date	Mar 17, 2015
Publication date	Sep 22, 2016
Grant date	—

Abstract

An optical transmission apparatus for transmitting pulsed light includes a dispersion medium having a negative dispersion parameter in a wavelength band of incident pulsed light, a first fiber which receives the pulsed light that has passed through the dispersion medium and has a negative dispersion parameter in a wavelength band of the incident pulsed light, and a second fiber which receives the pulsed light that has passed through the first fiber and has a positive dispersion parameter in a wavelength band of the incident pulsed light. The dispersion medium and the second fiber have positive dispersion slopes. The first fiber has a negative dispersion slope.

First claim

What is claimed is:

1 . An optical transmission apparatus for transmitting pulsed light, comprising:
a dispersion medium configured to transmit incident pulsed light and having a negative dispersion parameter in a wavelength band of the incident pulsed light; a first fiber which receives the pulsed light that has passed through the dispersion medium and has a negative dispersion parameter in a wavelength band of the incident pulsed light; and a second fiber which receives the pulsed light that has passed through the first fiber and has a positive dispersion parameter in a wavelength band of the incident pulsed light, wherein the dispersion medium and the second fiber have positive dispersion slopes, and wherein the first fiber has a negative dispersion slope.

2 . The optical transmission apparatus according to claim 1 ,
wherein the dispersion medium is configured to satisfy Expressions (1), (2), (3) and (4),
LD<LNL   (1)

L
D

=

T
0
2

b
2

(
2
)

where T 0 represents a pulse width of pulsed light that enters the dispersion medium,
b 2 represents group velocity dispersion per unit length of the first fiber,
P 0 represents peak power of pulsed light that enters the dispersion medium,
P 1 represents peak power of pulsed light that has just passed through the dispersion medium,
γ represents a nonlinear coefficient of the first fiber,
L 1 represents a length of the dispersion medium in a direction of an optical axis of the pulsed light that enters the dispersion medium, and
b nd represents group velocity dispersion per unit length of the dispersion medium, and
wherein, in a frequency range of the pulsed light that enters the dispersion medium, a total amount of dispersions b 2all is smaller than the pulse width T 0 of the pulsed light that enters the dispersion medium.

3 . The optical transmission apparatus according to claim 1 ,
wherein the first fiber and the second fiber are single-mode fibers, and wherein a zero dispersion wavelength of the first fiber is longer than a zero dispersion wavelength of the second fiber.

4 . The optical transmission apparatus according to claim 1 , wherein a zero dispersion wavelength of the second fiber is shorter than a wavelength of the pulsed light that enters the dispersion medium.

5 . The optical transmission apparatus according to claim 1 , wherein a pulse width of pulsed light that enters the dispersion medium is equal to or less than 100 femtoseconds.

6 . The optical transmission apparatus according to claim 1 , further comprising:
an optical unit configured to concentrate pulsed light onto the dispersion medium to enter the pulsed light into the dispersion medium; and a casing in which the dispersion medium and the optical unit are disposed, wherein the casing and the first fiber are connected.

7 . The optical transmission apparatus according to claim 6 , wherein the casing is connected to an output fiber of a light source that outputs pulsed light to the dispersion medium.

8 . The optical transmission apparatus according to claim 1 , wherein the dispersion medium contains silicon.

9 . The optical transmission apparatus according to claim 1 , wherein the first fiber and the second fiber contain silicon dioxide.

10 . An information acquisition apparatus to acquire information about a specimen, comprising:
a generating unit configured to generate a terahertz wave upon receipt of pulsed light; an irradiation unit configured to irradiate the specimen with a terahertz wave generated by the generating unit; and a detection unit configured to detect a terahertz wave from the specimen; and a transmission unit configured to transmit pulsed light output from a light source to the generating unit or to the detection unit, wherein the transmission unit is the optical transmission apparatus according to claim 1 .

11 . An apparatus for generating or detecting a terahertz wave comprising:
the optical transmission apparatus according to claim 1 , and an element configured to generate or detect a terahertz wave upon receipt of pulsed light from the optical transmission apparatus.

12 . The apparatus according to claim 11 , wherein the element includes a photoconductive element.

13 . The apparatus according to claim 11 , wherein the element contains nonlinear crystal.

Assignees

• Canon Kk

Inventors

• Yukawa Mitsuyoshi

Classifications

• G02B6/29394 Primary

  Compensating wavelength dispersion (G02B6/29376 takes precedence; dispersion compensated optical transmission systems H04B10/2507) · CPC title

• H01S3/0092

  Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity (nonlinear frequency conversion per se G02F1/35) · CPC title

• G02B6/02261

  Dispersion compensating fibres, i.e. for compensating positive dispersion of other fibres · CPC title

• H01S3/0057

  Temporal shaping, e.g. pulse compression, frequency chirping (soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108) · CPC title

• H01S3/11

  Mode locking; Q-switching; Other giant-pulse techniques, e.g. cavity dumping · CPC title